TITLE: GCN CIRCULAR NUMBER: 40641 SUBJECT: Fermi GRB 250606A: Global MASTER-Net observations report DATE: 25/06/06 06:31:54 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs lipunov@xray.sai.msu.ru
V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 250606A ( Fermi GBM team, GCN 40640) errorbox 91 sec after trigger time at 2025-06-06 04:30:12 UT, with upper limit up to 19.3 mag. Observations started at twilight. The observations began at zenith distance = 50 deg. The sun altitude is -13.2 deg.
MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 250606A errorbox 133 sec after trigger time at 2025-06-06 04:30:55 UT, with upper limit up to 19.0 mag. The observations began at zenith distance = 69 deg. The sun altitude is -81.6 deg.
The galactic latitude b = -38 deg., longitude l = 298 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2894070
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________
101 | 2025-06-06 04:30:12 | MASTER-SAAO | (02h 08m 41.74s , -77d 25m 10.8s) | C | 20 | 18.5 | 136 | 2025-06-06 04:30:12 | MASTER-SAAO | (02h 08m 41.71s , -77d 25m 10.8s) | C | 90 | 19.3 | Coadd 101 | 2025-06-06 04:30:12 | MASTER-SAAO | (02h 17m 05.10s , -77d 40m 08.2s) | C | 20 | 18.4 | 136 | 2025-06-06 04:30:12 | MASTER-SAAO | (02h 17m 05.14s , -77d 40m 08.2s) | C | 90 | 19.2 | Coadd 145 | 2025-06-06 04:30:51 | MASTER-SAAO | (02h 08m 41.54s , -77d 25m 10.8s) | C | 30 | 18.7 | 145 | 2025-06-06 04:30:51 | MASTER-SAAO | (02h 17m 04.94s , -77d 40m 08.4s) | C | 30 | 18.6 | 149 | 2025-06-06 04:30:55 | MASTER-OAFA | (02h 17m 57.07s , -77d 44m 13.6s) | C | 30 | 16.1 | 185 | 2025-06-06 04:31:31 | MASTER-OAFA | (02h 17m 56.58s , -77d 44m 12.6s) | C | 30 | 15.8 | 199 | 2025-06-06 04:31:40 | MASTER-SAAO | (02h 08m 41.15s , -77d 25m 10.8s) | C | 40 | 18.9 | 199 | 2025-06-06 04:31:40 | MASTER-SAAO | (02h 17m 04.63s , -77d 40m 08.5s) | C | 40 | 18.8 | 226 | 2025-06-06 04:32:07 | MASTER-OAFA | (02h 17m 56.05s , -77d 44m 11.8s) | C | 40 | 16.1 | 263 | 2025-06-06 04:32:40 | MASTER-SAAO | (02h 08m 40.59s , -77d 25m 10.4s) | C | 50 | 18.9 | 263 | 2025-06-06 04:32:40 | MASTER-SAAO | (02h 17m 04.32s , -77d 40m 08.4s) | C | 50 | 18.8 | 277 | 2025-06-06 04:32:53 | MASTER-OAFA | (02h 17m 55.51s , -77d 44m 10.8s) | C | 50 | 17.0 | 337 | 2025-06-06 04:33:48 | MASTER-SAAO | (02h 08m 40.02s , -77d 25m 10.1s) | C | 60 | 18.9 | 337 | 2025-06-06 04:33:48 | MASTER-SAAO | (02h 17m 03.91s , -77d 40m 08.3s) | C | 60 | 18.8 | 376 | 2025-06-06 04:34:22 | MASTER-OAFA | (02h 17m 54.36s , -77d 44m 09.3s) | C | 70 | 16.6 | 457 | 2025-06-06 04:35:38 | MASTER-OAFA | (02h 17m 53.34s , -77d 44m 08.1s) | C | 80 | 16.0 | 552 | 2025-06-06 04:37:04 | MASTER-OAFA | (02h 17m 52.34s , -77d 44m 06.6s) | C | 100 | 17.2 | 633 | 2025-06-06 04:38:44 | MASTER-SAAO | (02h 01m 01.33s , -78d 21m 33.4s) | C | 60 | 18.4 | 693 | 2025-06-06 04:38:44 | MASTER-SAAO | (02h 01m 01.32s , -78d 21m 33.4s) | C | 180 | 18.9 | Coadd 633 | 2025-06-06 04:38:44 | MASTER-SAAO | (02h 10m 05.68s , -78d 36m 27.8s) | C | 60 | 18.2 | 693 | 2025-06-06 04:38:44 | MASTER-SAAO | (02h 10m 05.70s , -78d 36m 27.8s) | C | 180 | 18.9 | Coadd 702 | 2025-06-06 04:39:19 | MASTER-OAFA | (02h 10m 51.22s , -78d 38m 24.3s) | C | 130 | 17.1 | 712 | 2025-06-06 04:40:03 | MASTER-SAAO | (02h 01m 00.54s , -78d 21m 33.2s) | C | 60 | 18.2 | 712 | 2025-06-06 04:40:03 | MASTER-SAAO | (02h 10m 05.03s , -78d 36m 27.9s) | C | 60 | 18.1 | 791 | 2025-06-06 04:41:22 | MASTER-SAAO | (02h 00m 59.70s , -78d 21m 32.7s) | C | 60 | 18.1 | 791 | 2025-06-06 04:41:22 | MASTER-SAAO | (02h 10m 04.49s , -78d 36m 27.5s) | C | 60 | 17.9 | 849 | 2025-06-06 04:41:35 | MASTER-OAFA | (02h 10m 49.35s , -78d 38m 22.1s) | C | 150 | 17.0 | 870 | 2025-06-06 04:42:41 | MASTER-SAAO | (02h 00m 58.99s , -78d 21m 32.4s) | C | 60 | 17.8 | 870 | 2025-06-06 04:42:41 | MASTER-SAAO | (02h 10m 03.94s , -78d 36m 27.3s) | C | 60 | 17.8 | 1020 | 2025-06-06 04:44:12 | MASTER-OAFA | (02h 10m 47.45s , -78d 38m 19.3s) | C | 180 | 17.4 | 1206 | 2025-06-06 04:47:18 | MASTER-OAFA | (02h 10m 44.99s , -78d 38m 15.8s) | C | 180 | 14.2 | 3930 | 2025-06-06 05:32:42 | MASTER-OAFA | (02h 02m 27.41s , -77d 24m 58.8s) | C | 180 | 18.4 | 4117 | 2025-06-06 05:35:48 | MASTER-OAFA | (02h 02m 25.46s , -77d 24m 53.1s) | C | 180 | 18.4 | 4304 | 2025-06-06 05:38:55 | MASTER-OAFA | (02h 02m 23.74s , -77d 24m 48.4s) | C | 180 | 19.0 | 4490 | 2025-06-06 05:42:01 | MASTER-OAFA | (02h 02m 21.86s , -77d 24m 43.4s) | C | 180 | 18.9 | Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
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